I have had no bugs completing the mission but the reward from the crate that is a level reward i have not received on 2 of 3 characters i have played the mission with, i have received the accolade but not the reward box?
On my primary i was able to complete and received all rewards
It's nothing special. It's a character bound version of the old "level appropriate item" crate. It's a totally random item that might be total junk. Or it might be a purple MK11 Neutronium.... you never know. And no you can't farm the crate because opening the crate is linked to having the accolade.
Also.... the reward box USUALLY auto opens itself.... USUALLY. So a lot of the time you'll never see the reward box in inventory.